Instant drying photostat



United States Patent INSTANT DRYING PHOTOSTAT Max H. Goldschein, Washington, D. C.

Application January 29, 1953, Serial No. 334,107

1 Claim. (Cl. 96-84) (Granted under Title 35, U. S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States for governmental purposes without the payment to me of any royalty thereon in accordance with the provisions of the act of April 30, 1928 (Ch. 460, 45 Stat. L. 467).

This invention relates to photographic materials and, more particularly, to light sensitive elements for use in rapidly copying documents, drawings, and the like, under conditions present in the usual ofiice.

The photographic elements used in commercial or large scale copying or reproducing establishments generally consists of sheets of white paper coated with a suitable light sensitive material, such as silver halide emulsion. This paper is stored under conditions preventing its exposure to actinic rays, and after its exposure in the printing operation, it must be carefully protected from further exposure during subsequent handling in developing and fixing operations. Since the paper is porous, it absorbs liquid and becomes thoroughly wet during development and washing. Dark rooms and expensive handling and drying equipment are necessary in photographic reproduction with this type of material.

' The operations are also time consuming.

It is frequently desirable to make a photographic copy of a document, drawing, or the like, for immediate use, under conditions where it is inconvenient or impossible to remove the original to a photographic establishment provided with the customary bulky apparatus, dark rooms, and washing and drying equipment. Small offices may resort to the use of less complicated apparatus with improvised dark rooms, but this unduly disturbs the oflice routine and time is lost in drying the washed prints. The portable self-contained photocopying apparatus disclosed in my Patent No. 2,557,097 solves many of the problems encountered in small scale photographic reproduction work of the type described. However, when the usual photosensitive paper is used in this apparatus, a special covering sheet of tinted cellophane, or the like, must be used as a cover for daylight handling of the exposed print, and the final washed print must be squeezed and blotted free of the absorbed moisture. Unskilled operators may have difficulty in avoiding overexposure of the print during the handling thereof.

An object of this invention is to provide a light sensitive material for photocopying, of the type described, which may be handled under substantially daylight conditions and which after developing, fixing and washing may be quickly dried for immediate use.

Another object of this invention is to provide a light sensitive material for photocopying which is substantially hydrophobic and which is protected on one side from the passage of actinic rays.

Another object of this invention is to provide photographic sheet materials of water resistant plastic coated or impregnated to provide a white background and provided on one side with a red-tinted layer and on the opposite side with a light sensitive emulsion.

'ice

These and other objects and advantages of the invention will become apparent from the following descrip tion, and from the drawings, in which:

Fig. 1 is an enlarged, diagrammatic, fragmentary, sectional view of light sensitive plastic sheet materials illustrating one embodiment of the invention.

Fig. 2 is a view similar to that of Fig. 1 of light sensitive sheet material illustrating another form of the invention.

Fig. 3 is a view similar to that of Fig. 1 of light sensitive sheet material illustrating another form of the invention.

Fig. 4 is a view similar to that of Fig. 1 of light sensitive sheet material illustrating still another form of the invention.

The photographic material of this invention comprises, in general, a transluscent or semi-opaque, water-resistant sheet, one side of which is sensitive to light and the other side of which is tinted to retard the passage of actinic rays.

The photographic sheet materials are made up of a flexible support of white, substantially hydrophobic, or water-resistant plastic material, or of a hydrophobic plastic material pigmented or coated with a suitable substance to provide a white background having a coating of light sensitive emulsion on one side, and having a red tint on the opposite side of the sheet from the light sensitive material to retard the passage of light rays. The tinted surface may be in the form of a separate water-resistant, water soluble, or strippable plastic coating, or may comprise a permanent part of the plastic support as hereinafter specified.

Suitable water-resistant support materials comprise plastic sheet or film material fabricated from polyvinyl chloride, polythene, vinylidene chloride polymers and copolymers known to the art as Saran, polystyrene, methyl methacrylate polymer, and the like. Regenerated cellulose, such as cellophane, Which has been rendered moisture resistant during the process of manufacture may also be used as support materials. For example, Saran-coated cellophane, which is high resistant to moisture, may be employed. Cellulose acetate and other plastics that normally absorb moisture, or possess low water resistance, may likewise be waterproofed by suitable surface coatings or by other means applied during the process of manufacture, and may subsequently be utilized as support materials in accordance with this invention. Suitable support material may also comprise paper made hydrophobic or Water-resistant by incorporating a suitable water-resistant plastic or resin binder with said paper. For example, the paper may be impregnated with polystyrene, or it may be coated with methyl methacrylate polymer, or with vinylite resins. All of the above mentioned materials are generally designated herein as water-resistant plastic sheet material. It will be understood that the plastic sheet materials should incorporate suflicient plasticizers to render them adequately flexible for rolling without cracking or breaking.

In order to provide a proper white background for photoprinting, the plastic support material is pigmented during its process of manufacture or is coated with a suitable white pigment material after being formed into sheets. Metal oxides such as titanium dioxide, zinc oxide, and the like may be used as the pigment for impregnating or coating the plastic support. Suificient white pigment is employed to render tthe sheet material transluscent or substantially opaque. However, the resulting white sheet should permit the passage of actinic rays for reasons hereinafter apparent. Ordinary White paper WhlCll has been waterproofed by the methods described provides an adequate background.

Where the water-resistant plastic sheet material includes a white pigment whereby the proper background may be incorporated in a suitable solvent and applied as a thin layer to one side of the white support material. Alternatively, a separate red-tinted plastic sheet may be cemented to the support sheet with a'suitable plastic cement. This sheet may be attached in such a manner is easily applied and sufiiciently flexible may beusedas the support coating.

A light sensitive emulsion, such as gelatin containing that it can be stripped from the support if desired. It will -1 be understood that any red-tinted plastic material which silver salts, is now applied to the side of the support opposite the tinted coating. Should difficulty be encountered with some of the water-resistant materials ,in securing adequate adhesion of the gelatin layer, a .suit- 'able' substratum material may .first be applied in the V manner known to the art.

In a further embodiment of the invention, a red-tinted,

wvater-resistant plastic sheet material is utilized as the support.

form the background for printing. The light sensitive This is coated witha suitable white pigment-to emulsion is then applied over the pigment layer.

Referring now to the drawings 'for a..more detailed description of theinvention, Fig. 1:shows a-white,.waterresistant, plasticsupport, such as polyvinyl chloride containing a small amount of titaniumdioxide, having a coating 11 on one sidelthereof of redetinted material such as polyvinyl chloride or of. gelatin tinted with a suitable red dye. The material form-ingthe coating'll may be dissolved or stripped off during developing operations if desired. The other side of the support 10 from the tinted layer 11 is provided with a. coating of silver halide gelatin emulsion 12.

In the embodiment of the' invention shown in Fig.12

- of the drawings, a red-tinted, water-resistant plastic; sheet forms a support 14. This support is. coated with a suitable plastic coating agent containing a 'small'amount of white pigment to form layer 15. 'The gelatin silver-halide emulsion is applied over the white pigment layer; 15 [to forma second layer '16.

In a third embodiment'of the. invention, as illustrated in Fig. 3, a whitewater-resistant support 17comprises :paper which has been impregnated with polystyrene. This support is'coated on one side with red-tinted polyvinyl 'chloride, gelatin, or. the like, to form layer :18.

The silver-halide emulsion formsa layer 19 on the oppo- 1 site side from the timed coating .as in the. embodiment described in Fig. 1.

Fig; 4 shows a white pap'er '20 utilized as a support coated on one sidewith athin coating of transparent -'polyvinyl chlorideaand.ioniithe other side with a red tinted polyvinyl chloride layer 22. The paper '20. is rendered water-resistant'bythe coating materials,-and one of the coating layers serves to retard the passage ofactinic rays. The tintedlayer 22 in :thisinstance must be water resistant. The gelatin; silveremulsion is applied on the opposite side of thexsupport 20 from the tinted coating ZZ and over the transparent layer 21'to form lightsensitive'layer 23.

Each of the light sensitive sheet materials described above is;highlywaterresistant. The gelatin-silver h'alide emulsion is relatively thin and absorbs very little moisture during development, fixing'and washing. The tinted coating is either water resistant, as, for example, when polyvinyl chloride is used,"or washes away in the developing bathas in -the caseYof gelatin. After the Washing operation, it is merelyenecessary to blotor spongethe prin't to remove droplets ofsvater and the -print is sufii- ,y-yciently-dryforiimmediateause;

The photographic material described herein may be stored in the form of a roll, preferably with the redtinted layer on the outer portion thereof to protect the light sensitive layer from exposure during handling. The material may be placed in any suitable device for exposure under a negative or under a document as the case may be. A suitable portable device for rapid photoprinting is described in my aforementioned Patent Number 2,557,097.

When a copyof a document is to be made and the document is printed on one side only, the light sensitive material is placed in the exposure device with the light sensitive emulsion side up. face up on top of the light sensitive sheet. The material is then exposed for a suitable time to light passing through Ordinary daylight may be used for the document. making the exposure, or light from an incandescent lamp may be directed through the document to the light sensitive surface. After the proper exposure time, thedocument and sensitized sheet are removed from the exposure device and the sensitized sheet is quickly rolled up into a tight cylinder with the tinted layer outside. The roll of material may now be transported to the developing and fixing bath without further exposure. Where my portable device is used the developing, fixing, and washing liquids are contained in bottles and the roll of material is dipped first into the developing solution, then into the washing water, and then into the fixing solution and back intothe wash water. The print is thereby developed,

fixed and washedcn the spot. It is now merely necessary toblot-or sp onge any adhering water from the print prior. to' its use. he Water-resistant plastic material from which-the print is made prevents absorptionof moisture which would require the usual prolonged drying opera tions. -The-red-tinted outer layer retards the passage of actinic rays and prevents exposure prior to the developmentof the print. It will be understood. that the procedure--would-be generally similar Where means other than -my'portable apparatus are used for exposing, de-

veloping, fixing,- and washing the print. However, greater care must be taken in most instances to avoid undue .ex-

posure-ofthe -print. In most operations, thiscan be avoided by-keeping-the red-tinted surface between the -light-and the light sensitive side of the sheet.

1f thedocuinent to becopied is printed on both sides,

she document is placed inan exposureidevice with the surface to beprinted facingupward. .The sheet material of this invention is then placed over thedocument with the sensitized side down. The exposure is made by directing light through-thephotosensitivesheet to the document.

' If the tintingis of a permanent type, the tinted surface retards-the passage of actinic rays and aprolonged exposure must be made. Where the tinting is in the form -of astrippable coating such coating is removed prior to "the-exposure. After the exposure is made, the print is developed asdescribed above, the resulting print .being a reverse ormirrorimage negative. The reverse negative is powplaced over a new sheet of sensitized paper having its-emulsion side up. The exposure and development are carried out as before and a positive print results. The

time and equipment saved in dryingthe prints more than compensates for the extra time required in makingthe -exposure-evenwherethe tinting isof a permanent type, b and theprints'may be more readily handled by amateurs without overexposure. 7 7

While the invention has been described with particular --reference-tuthe copying of documents, drawingsp' and the like, it willbe understood that the materials described may be-utilized for any purpose wherein a rapid-drying, lightprotected printing roll is desired Thephotographic material shown above is by way of 'exampleonly 'and many modifications will occur to those skilled in the art'withinthe scope of the invention.

What is claimed is:

A rapid-drying,light-protected, non-pro ectible, com-- The document is placed posite printing sheet comprising an opaque, water-impervious, flexible white sheet of polyvinyl chloride impregnated with zinc oxide, a light-sensitive silver halide coating on one surface of the sheet adapted to reproduce a latent image on exposure to light, the sheet carrying red tinting spaced from the light-sensitive coating resisting the passage of actinic rays through the sheet when rolled in storage, whereby further exposure of the latent image prior to development of the print is prevented, and the unrolled developed print immediately when drawn from developing, fixing and washing baths is substantially in dry condition.

References Cited in the file of this patent UNITED STATES PATENTS 1,597,727 DeSperati Aug. 31, 1926 6 Lohofer June 7, 1927 McMaster Jan. 8, 1935 Tucker May 7, 1940 Hunter Nov. 16, 1954 FOREIGN PATENTS Great Britain of 1899 Great Britain Apr. 25, 1918 Great Britain July 1, 1927 Great Britain May 7, 1930 Great Britain May 8, 1930 Great Britain Aug. 8, 1929 Great Britain of 1931 Great Britain July 13, 1939 Great Britain Aug. 16, 1939 

